Manufacture of screw-cutting oil



H. C. CLAFLIN.

MANUFACTURE OF SCREW CUTTING OIL.

APPLICATION FILED MAR.22, 1920. RENEWED NOV. 5, 1921.

1,401,760. Patented Dec- 27, 1921.

HARRY C. CLATFLIN, OF CLEVELAND, OHIO.

KANU'FAGTURE OF SCREW-CUTTING OIL.

Application filed March 22, 1920, Serial No. 367,605. Renewed November 5, 1921.

T 0 all whom it may concern Be it known that I, HARRY C. CLAFLIN, a citizen of the United States, and resident of Cleveland, county of Cuyahoga, and State of Ohio, have invented certain new and useful Improvements in the Manufacture of Screw-Cutting Oil, of which the following is a specification, and which are illustrated in the accompanying drawings, forming a part thereof.

The invention relates to the compounding of lubricants and to the improved product, having particular reference to lubricants for metal cutting tools which operate at high speed. While it has been recognized that the addition of sulfur to oil is desirable for producing a compound which is useful to reduce the overheating of metal cutting tools, it is believed that no permanent colloidal solution of sulfur in oil has heretofore been produced and that no satisfactory method of compounding these materials has been known. The object of the invention is therefore to provide an improved method of compounding sulfur with oil and to produce a permanent mixture of these materials.

Apparatus in which the improved method may be practised is conventionally represented in the accompanying drawings wherein;

Figure 1 is a central vertical section of a mixing kettle and furnace for heating the same;

Fig. 2 is an elevation of the complete apparatus, some parts being shown in section, and

Fig. 3 is a plan view of the apparatus illustrated in Fig. 2.

The improved product comprises a permanent colloidal solution of sulfur in oil preferably in the proportion of about 5 lbs. of sulfur to 30 gallons of the product and without the addition of either, animal or vegetable oils or other substances. The steps of a preferred method or process by which this product may be produced include the following:

(1) Mixing finely divided sulfur with a small quantity of a heavy mineral oil to produce a thick paste. For this purpose 5 lbs. of sulfur may be mixed with one quart of the heavy mineral oil commonly known as 600 steam refined cylinder oil. Finely divided sulfur in any one of its allotropic Specification of Letters Patent.

Patented Dec. 2'3, 3921.

Serial No. 513,213.

forms may be used but the crystalline form commonly known as brimstone ground to a lne powder is most convenient. No heat is required for the making of this paste;

(2) Gradual addition of the paste to a much larger quantity of the same heavy mineral 011 while heated and vigorously agitated. In carrying out this step of the process the paste prepared by the mixture of 5 lbs. of sulfur with one quart of mineral oil may be added gradually to 10 gallons of the 600 cylinder oil While the latter is maintamed at a temperature about 220 C. with constant stirring of the mixture continuing for at least one minute after all of the paste has been added;

(3) Gradual addition of the hot mixture of sulfur and heavy mineral oil prepared by steps one and two, to a quantity of non-vis cous neutral mineral oil while the latter is malntalned at a low temperature and thoroughly agitated. For this purpose the quantlty of the mixture prepared with 5 lbs. of sulfur and 10 gallons of 600 cylinder oil may be added to 20 gallons of parafiin oil of 34 B.

While the temperature of the hot mixture of heavy mineral oil and sulfur iscapable of some variation there appears to be a critical temperature at about 195 0. below which the colloidal efi'ect described will not be completely produced on addition of the hot mixture to the cold oil. However, the best operating condition seems to be obtained at the aforementioned temperature of 220 C. As is well known, these temperatures are above those at which melted sulfur is most fluid. In fact, the higher temperature of 220 C. closely approaches that at which melted sulfur becomes a thick pasty mass. As melted sulfur changes gradually from the said fluid condition to the pasty condition, there is believed to be no definite temperature at which the colloidal efi'ect described will be obtained as to all of the added sulfur and immediately below which it will not be obtained as to any of the added sulfur. Nevertheless, the range of permissible temperatures is quite narrow, the result being a product in which some of the sulfur will be precipitated from the oil on standing, if the temperature is too low and a product in which some of the sulfur is chemically combined with the oil if the temperature is too high.

Use of the s0-called 600 cylinder oil as the medium with which the sulfur is mixed when heated is desirable to avoid danger from fire. Likewise, the addition of the said mixture of heavy cylinder oil and sulfur to a larger quantity of paraffin oil produces a roduct which has the desired viscosity. owever, it is believed that the important step in obtaining the said colloidal solution of sulfur in oil is that of bringing the sulfur to a temperature at which melted sulfur becomes thickened to a marked degree, in the presence of oil with which sulfur does not combine chemically at that temperature.

The apparatus illustrated in the accompanying drawings comprises a tank 10 from which small quantities of mineral oil may be drawn into a mixing vat 11 which is equipped with a mechanical stirring device 12. Preferably a sieve 13 is supported over the vat 11 through which the finely divided sulfur is added to the quantity of cylinder oil contained in the vat. When a smooth paste has been produced by thorough stirring of the mixture of the cylinder gil and sulfur, it is drawn from the bottom of the vat 11 to a container 14 by which it is transferred to the mixing kettle 15.

ed in a furnace 16 and the kettle is equipped with a mechanical stirring device 17. In carrying out the improved process the quantity of. 600 cylinder oil contained in the mixing kettle 15 is preferably brought to a temperature of 220 C. before the addition of the paste prepared in the vat 11. After complete addition of the paste to the quantity of material contained in the kettle and continued stirring for at least one minute, these mixed materials are drawn from the bottom of the kettle 15 through pipe 18 into the cold mineral oil contained in the cooling vat 19.

n order that the addition of the heated mixture of sulfur and cylinder oil prepared in the kettle 15 may not materially raise the temperature of the cold mineral oil contained in the vat 19, the cooling vat 19 is preferably provided with a jacket 20 through which cold water is circulated, and the size of the pipe 18 is such that the delivery of the hot mixture to the vat may be comparatively slow.

As it is desirable that the oil contained in the cooling vat 19 should be thoroughly stirred during the addition of the hot mixture, a mechanical stirring device 21 is mounted in the vat. If desired this mechanical stirring device may be driven by power through a belt pulley 22 and beveled gears 23, 24. In the apparatus illustrated, the mixlng vat 11 is proportioned to prepare at one t1me a suflicient quantity of the paste for addition to the amount of cylinder. oil which may be heated in the kettle 15 at one charge while the cooling vat 19 is desirably of such size as to contain a quantity of light mineral oil for the addition of several charges of the heated mixture prepared in kettle 15. When the several parts of the apparatus are so proportioned the mixing vat 11 and kettle 15 may be maintained in substantially continuous operation without danger of over-heating the product prepared in the cooling vat 19.

The product is a thin fluid at ordinariy temperatures and of a dark brown color. t is valuable for use as a lubricant in the operation of screw machines and the like. Under a high power microscope the minute individual particles of sulfur show rotary motion in the supporting medium characteristic of a true colloidal condition as distinguished from a mere mechanical mixture of the-ingredients. The compound is thus uniform and permanent and the product may be stored indefinitely without separation of any substantial part of the sulfur.

While the product comprises preferably colloidal sulfur in mineral oil it is evident that this product may be diluted with animal or vegetable oil, or other liquid without departing from the invention, .or in any way As shown, the mixing kettle 15 is support-' lessening the beneficial effect due to the presence of the particles of colloidalsulfur.

I claim as my invention:

1. The method of preparing a heat absorbing lubricant which consists in mixing sulfur with a heavy mineral oil to form a paste, stirring the paste into a larger quantity of heavy mineral oil while heated and gradually adding the hot mixture of sulfur and heavy mineral oil to astill larger quantity of cold light mineral oil, the said mixture of sulfur and mineral oil'being at such a temperature as to produce substantially permanent suspension of the sulfur in the mineral oil.

2. The method of preparing a heat absorbing lubricant which consists in stirrin sulfur into a quantity of heavy mineral 01 and gradually adding the mixture of sulfur and heavy mineral oil to a larger quantity of light mineral oil, the said mixture of sulfur and mineral oil being at such a temperature as to produce substantially permanent suspension of the sulfur'in the mineral oil.

3. The method of preparing a heat absorbing lubricant which consists in stirring sulfur into a quantity of heavy mineral oil while heated and gradually adding the mixture of sulfur and heavy mineral oil to a 12 0 larger quantity of cold light mineral oil, the said mixture of sulfur and mineral oil being at such a temperature as to produce substantially permanent suspension of the sulfur in the mineral oil.

4. The method of preparing a heat absorbing lubricant which consists in stirring a hot mixture of sulfur and heavy mineral oil into a larger quantity of cold light mineral oil, the said mixture of sulfur and min- 130 eral oil being at such a temperature as to produce substantially permanent suspension of the sulfur in the mineral oil.

5. The method of preparing a heat absorbing lubricant which consists in stirring a hot mixture of sulfur and oil into a larger quantity of cold oil, the said mixture of sulfur and oil being at such a temperature as to as to produce substantially permanent suspension of the sulfur in the oil.

7. A heat absorbing lubricant comprising a colloidal solution of sulfur in oil.

8. A heat absorbing lubricant comprising a colloidal solution of sulfur in mineral oil.

9. A heat absorbing lubricant comprising a colloidal solution of sulfur in a mixture of heavy cylinder oil with light paraflin oil.

10. A heat absorbing lubricant comprising a colloidal solution of sulfur in a mixture of 600 steam refined cylinder oil with paraffin oil.

11. A heat absorbing lubricant comprising a colloidal solution of sulfur in a mixture of heavy cylinder oil with twice the quantity of light parafiin oil.

12. A heat absorbing lubricant comprising a colloidal solution of sulfur in a mixture of 600 steam refined cylinder oil with twice the quantity of paraflin oil.

18. A screw cutting compound comprising mineral oil containing a substantial amount of sulfur, the major portion of which sulfur is in colloidal solution.

14. A screw cutting compound comprising mineral oil without animal or vegetable fat and containing a substantial amount of sulfur, the major portion of which sulfur is in colloidal solution.

15. A screw cutting compound comprising oil containing a substantial amount of sulfur, the major portion of which sulfur is in colloidal solution.

'16. The method of preparing a screw cutting compound comprising oil containing a substantial amount of sulfur which consists in heating a mixture of the sulfur and oil to the temperature at which melted sulfur thickens, the oil being mainly of mineral origin ,characterized by being chemically inert with respect to sulfur at that temperature.

17. The method of preparing a screw cutting compound comprising oil'containing a substantial amount of sulfur which consists in heating a mixture of the sulfur and oil to the temperature at which melted sulfur thickens and rapidly cooling the said heated mixture, the oil being mainly of mineral origin characterized by being chemically inert with respect to sulfur at the temperature to which the said mixture is heated.

HARRY C. CLAFLIN. 

